This is kinda. Non reproducible issue , which I have observed.
Auto Update doesn't work when IE6 is installed... If i install IE8 it works fine ...
most of the time...with many users ....auto update works fine even with IE6 also.
How to check if you have this problem:
Right click in on tray icon and check for updates...PMW must tell you one of following
1) if you are on latest version
2) there is an newer version available.
If it doesn't tell you that, then I am sorry to say that you are also one of the victim of this bug.
You can go to PMW.log ( Located at <AppData>\PMW\2.0\ )
and check what's the error... does it say "Interface not Registered" ?
What to do if you have this problem:
Install IE8 , now you will notice it will start working.
Now even if you uninstall IE8 it MAY work.
DEV NOTE:
Looks like it got something to do with System requirement.
I have posted on Microsoft's MSXML forum but did not get any reply..